Filter systems for separating microcarriers from cell culture solutions

ABSTRACT

A filter assembly for separating microcarriers from a fluid medium includes a collapsible container bounding a sterile compartment adapted to hold a fluid. An inlet port is attached to the container through which fluid flows into the compartment. An outlet port is attached to the container through which fluid flows out of the compartment. A filter is disposed within the compartment, the filter dividing the compartment into an inlet chamber that is fluidly coupled with the inlet port and an outlet chamber that is fluidly coupled with the outlet port, the filter allowing a medium to pass therethrough but preventing microcarriers disposed in the medium from passing therethrough.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/540,967, filed Sep. 29, 2011, which is incorporated herein byspecific reference.

BACKGROUND OF THE INVENTION

1. The Field of the Invention

The present invention relates to filter systems and assemblies forseparating microcarriers from cell culture solutions.

2. The Relevant Technology

The use of microcarriers in the biopharmaceutical industry is wellknown. Microcarriers can support the growth of anchorage-dependent cellsthereon. Because of this, microcarriers are regularly used during cellculturing to optimize growth of various anchorage-dependent cell lines,such as protein-producing or virus-generating adherent cell populations,which are commonly used in the production of biologics (proteins) andvaccines.

Microcarriers have a surface chemistry that allows for attachment andgrowth of the anchorage dependent cells in cell culture procedures.Microcarriers can be made from a number of different materials andtypically have a density that allows them to be maintained in suspensionwith gentle stirring.

Microcarrier cell culturing is typically carried out in a bioreactor.During culturing, the cells grow on the surface of the microcarriers.Once the cell culturing process is completed, the cultured cells aredetached from the microcarriers through a chemical process carried outin the solution. The cultured solution containing the cells is thenseparated from the microcarriers for use or further processing. Thegathered microcarriers can be cleaned, sterilized, and re-used, or canbe discarded.

Separation of the microcarriers from the cultured solution that includesthe detached cells is typically achieved by passing the solution througha rigid container having a horizontal screen that extends across therigid container. The screen is a rigid mesh that allows the culturedfluid to pass through but prevents the microcarriers from doing so.However, as the microcarriers build up on the screen, they begin to clogthe screen and prevent the fluid from passing therethrough. Once thescreen is clogged, the process stops until the screen is unclogged.Furthermore, once the process is completed, the rigid container andrelated screen must be cleaned and sterilized before it can be reused.These process steps can be expensive and time consuming.

Accordingly, what is needed in the art are methods and/or systems thatcan alleviate one or more of the above problems.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the present invention will now be discussed withreference to the appended drawings. It is appreciated that thesedrawings depict only typical embodiments of the invention and aretherefore not to be considered limiting of its scope. In the drawings,like numerals designate like elements. Furthermore, multiple instancesof an element may each include separate letters appended to the elementnumber. For example two instances of a particular element “20” may belabeled as “20 a” and “20 b”. In that case, the element label may beused without an appended letter (e.g., “20”) to generally refer to everyinstance of the element; while the element label will include anappended letter (e.g., “20 a”) to refer to a specific instance of theelement.

FIG. 1 is a block diagram of a cell culturing system that uses a filtersystem according to one embodiment;

FIG. 2 is a perspective view of a filter system according to oneembodiment;

FIG. 3 is a cross sectional side view of the filter assembly of thefilter system shown in FIG. 2;

FIG. 4 is a cross sectional side view of the filter port and filtershown in FIG. 3;

FIG. 5 is a perspective view of the support housing of the filter systemshown in FIG. 2;

FIG. 6 is a cross sectional side view of the support housing of thefilter system shown in FIG. 2;

FIG. 7 is a cross sectional view of the filter system shown in FIG. 2taken along section line 7-7 of FIG. 2;

FIGS. 8A-8C are cross sectional side views of the filter and a portionof the filter port of the filter system shown in FIG. 2, showing fluidflow through the filter during various stages of use;

FIG. 9 is a cross sectional side view of a portion of a filter systemshowing one embodiment of a filter port that can be directly attached tothe support housing;

FIG. 10A is a cross sectional side view of a portion of a filter systemshowing another embodiment of a filter port directly attached to thesupport housing;

FIG. 10B is a perspective view of the clamp assembly of the filtersystem shown in FIG. 10A;

FIG. 11 is a cross sectional side view of a filter system in which analternative embodiment of a filter assembly is disposed within thesupport housing;

FIGS. 12A-12C are cross sectional side views of the filter assemblyshown in FIG. 11, showing fluid flow through the filter during variousstages of use;

FIG. 13 is a cross sectional side view of a filter system in whichanother alternative embodiment of a filter assembly is disposed withinthe support housing;

FIG. 14 is a cross sectional side view of the filter and outlet port ofthe filter assembly shown in FIG. 13;

FIGS. 15A-15C are cross sectional side views of the filter assemblyshown in FIG. 13, showing fluid flow through the filter during variousstages of use;

FIG. 16 is a cross sectional side view of an alternative embodiment of afilter/outlet port combination;

FIG. 17A is a perspective view of a hanger attached to the supporthousing;

FIG. 17B is a cross sectional side view of a portion of a filter systemshowing another embodiment of an inlet port directly attached to thesupport housing the hanger shown in FIG. 17A;

FIG. 17C is a perspective view of the clamp assembly shown in FIG. 17B;

FIG. 18 is an exploded perspective view of a retention ring havinghangers formed thereon and a related support housing;

FIG. 19 is a cross sectional side view of a filter system in whichanother alternative embodiment of a filter assembly is disposed withinthe support housing;

FIG. 20 is a cross sectional side view of the filter shown in FIG. 19;

FIG. 21 is an exploded perspective view of a portion of the filter shownin FIG. 20;

FIGS. 22A-22C are cross sectional side views of the filter assemblyshown in FIG. 19, showing fluid flow through the filter during variousstages of use;

FIG. 23A is an exploded perspective view of an alternative filter sheetconfiguration that can be used in the filter assembly shown in FIG. 19;

FIG. 23B is a cross sectional side view of a filter that incorporatesthe filter sheet configuration shown in FIG. 22A;

FIG. 23C is a cross sectional side view of a filter that incorporatesanother alternative filter sheet configuration;

FIG. 24A is an exploded perspective view of another alternative filtersheet configuration that can be used in the filter assembly shown inFIG. 19; and

FIG. 24B is a cross sectional side view of a filter that incorporatesthe filter sheet configuration shown in FIG. 23A.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As used in the specification and appended claims, directional terms,such as “top,” “bottom,” “left,” “right,” “up,” “down,” “upper,”“lower,” “proximal,” “distal” and the like are used herein solely toindicate relative directions in viewing the drawings and are notintended to limit the scope of the claims in any way.

The present invention relates to various apparatuses and methods foreffectively filtering microcarriers or other particulates out of a cellculture solution without clogging or otherwise impeding the flow of thesolution away from the microcarriers.

FIG. 1 depicts a cell culturing system 100 that incorporates embodimentsof the present invention. In cell culturing system 100, cells are grownwithin a biological container, such as bioreactor 102. Bioreactor 102can be a microgravity bioreactor, internally-stirred bioreactor,fluidized bed bioreactor, rocker bag bioreactor or any other type ofbioreactor known in the art. Bioreactor 102 can also be a rigid tankreactor that needs to be sterilized between uses or a single usebioreactor that includes a disposable bag. Other types of bioreactors orother biological containers can alternatively be used, such as, e.g., aspinner flask. The cells are grown in a nutrient growth medium that caninclude a variety of different components. The components are typicallydependent on the cell type and processing conditions. Growth mediums andrelated components are known in the art and are not discussed herein.

Microcarriers are added to the growth medium within the bioreactor sothat anchorage-dependent cells can grow thereon. The microcarriers canbe spherically shaped beads ranging between about 130 microns to about300 microns in diameter. Other sizes can also be used. It is alsoappreciated that the microcarriers can have alternative shapes buttypically have a maximum diameter in a range between about 130 micronsto about 300 microns. The microcarriers have a density that allows themto be maintained in suspension with gentle stirring. For example, themicrocarriers can also have a density of about 1.02 g/cm³ to about 1.10g/cm³. Other densities are also possible. The microcarriers can be madefrom a number of different materials including DEAE-dextran, glass,polystyrene plastic, acrylamide, and collagen. The different types ofmicrocarriers can differ in their porosity, specific gravity, opticalproperties, presence of animal components, and surface chemistries.Surface chemistries can include extracellular matrix proteins,recombinant proteins, peptides, and positively or negatively chargedmolecules. The microcarrier materials, along with the different surfacechemistries, can influence cellular behavior, including morphology,proliferation and adhesion.

During culturing, the cells grow on the surface of the microcarriersdisposed within the mixture. Once the cell culturing process iscompleted, a chemical reagent, such as an enzyme, is added to themixture, which includes the medium and the microcarriers suspendedwithin the medium. The chemical reagent causes the cells to detach fromthe microcarriers so that the cells are freely suspended within thegrowth medium. The mixture is then removed from the bioreactor 102 andpassed through a filter system 104. Filter system 104 includes a filterassembly 106 that can be housed in an optional support housing 108. Thefilter assembly 106 comprises a filter 170 disposed within a container112. Filter 170 separates the microcarriers from the cultured solution,which includes the growth medium and the detached cells, by allowing thecultured solution to pass therethrough while preventing themicrocarriers from doing so. Container 112 can be substantially rigid orflexible and can be disposable, if desired.

FIG. 2 shows a perspective view of filter system 104 including supporthousing 108 and filter assembly 106. Depicted in FIG. 3 is a crosssectional side view of filter assembly 106. In part, filter assembly 106includes container 112, a filter port 151 coupled to container 112 andfilter 170 coupled to filter port 151. Filter assembly 106 can alsoinclude one or more inlet ports and an outlet ports through which fluidcan flow into and out of container 112, respectively, as described inmore detail below. In one embodiment, container 112 comprises a flexibleand collapsible body 120, such as a flexible bag, having an interiorsurface 122 and an opposing exterior surface 124. Interior surface 122bounds a compartment 126. More specifically, body 120 comprises a sidewall 128 that, when body 120 is unfolded, has a substantially circularor polygonal transverse cross section that extends between a first end130 and an opposing second end 132. First end 130 terminates at a topend wall 134 while second end 132 terminates at a bottom end wall 136.

Body 120 is comprised of a flexible, water impermeable material such aspolyethylene or other polymeric sheets having a thickness in a rangebetween about 0.1 mm to about 5 mm with about 0.2 mm to about 2 mm beingmore common. Other thicknesses can also be used. The material can becomprised of a single ply material or can comprise two or more layerswhich are either sealed together or separated to form a double wallcontainer. Where the layers are sealed together, the material cancomprise a laminated or extruded material. The laminated materialcomprises two or more separately formed layers that are subsequentlysecured together by an adhesive.

The extruded material comprises a single integral sheet that comprisestwo or more layers of different material that can be separated by acontact layer. All of the layers are simultaneously co-extruded. Oneexample of an extruded material that can be used in the presentinvention is the HyQ CX3-9 film available from HyClone Laboratories,Inc. out of Logan, Utah. The HyQ CX3-9 film is a three-layer, 9 mil castfilm produced in a cGMP facility. The outer layer is a polyesterelastomer coextruded with an ultra-low density polyethylene productcontact layer. Another example of an extruded material that can be usedin the present invention is the HyQ CX5-14 cast film also available fromHyClone Laboratories, Inc. The HyQ CX5-14 cast film comprises apolyester elastomer outer layer, an ultra-low density polyethylenecontact layer, and an EVOH barrier layer disposed therebetween. In stillanother example, a multi-web film produced from three independent websof blown film can be used. The two inner webs are each a 4 mil monolayerpolyethylene film (which is referred to by HyClone as the HyQ BM1 film)while the outer barrier web is a 5.5 mil thick 6-layer coextrusion film(which is referred to by HyClone as the HyQ BX6 film).

The material is approved for direct contact with living cells and iscapable of maintaining a solution sterile. In one embodiment, thematerial can be sterilizable such as by ionizing radiation or otherconventional techniques. Other examples of materials that can be used indifferent situations are disclosed in U.S. Pat. No. 6,083,587 whichissued on Jul. 4, 2000 and United States Patent Publication No. US2003-0077466 A1, published Apr. 24, 2003 which are hereby incorporatedby specific reference.

In one embodiment, body 120 comprises a two-dimensional pillow style bagwherein two sheets of material are placed in overlapping relation andthe two sheets are bounded together at their peripheries to forminternal compartment 126. Alternatively, a single sheet of material canbe folded over and seamed around the periphery to form internalcompartment 126. In another embodiment, body 120 can be formed from acontinuous tubular extrusion of polymeric material that is cut to lengthand is seamed closed at the ends. In still other embodiments, such as inthe depicted embodiment, body 120 comprises a three-dimensional bag thatnot only has an annular side wall 128 but also a two dimensional top endwall 134 and a two dimensional bottom end wall 136. Three dimensionalcontainers can comprise a plurality of discrete panels, typically threeor more, and more commonly four or six. Each panel can be substantiallyidentical and can comprise a portion of the side wall, top end wall, andbottom end wall of the container. Corresponding perimeter edges of eachpanel can be seamed. The seams are typically formed using methods knownin the art such as heat energies, RF energies, sonics, or other sealingenergies.

In alternative embodiments, the panels can be formed in a variety ofdifferent patterns. Further disclosure with regard to one method ofmanufacturing three-dimensional bags is disclosed in United StatesPatent Publication No. US 2002-0131654 A1 that was published Sep. 19,2002 of which the drawings and Detailed Description are herebyincorporated by reference.

Although in the above discussed embodiment body 120 is in the form of aflexible bag, in alternative embodiments it is appreciated that body 120can also comprise any form of collapsible container or semi-rigidcontainer. Body 120 can also be transparent or opaque and can haveultraviolet light inhibitors incorporated therein.

It is appreciated that body 120 can be manufactured to have virtuallyany desired size, shape, and configuration. For example, body 120 can beformed having compartment 126 that is sized to hold in a range fromabout 10 liters to about 2,000 liters, with about 20 liters to about 250liters and about 20 liters to about 100 liters being more common. Othervolume sizes can also be used. Although body 120 can be any shape, inone embodiment body 120 is specifically configured to be substantiallycomplementary to a first chamber 232 (FIG. 6) of support housing 108, asdiscussed below.

Continuing with FIG. 3, one or more hanging tabs 140 can be mounted ontop end wall 134 or the upper end of sidewall 128 to support the upperend of body 120 within support housing 108, if used. For example, in thedepicted embodiment a plurality of radially spaced apart hanging tabs140 are positioned on top end wall 134 at or near the outer perimeterthereof. Each hanging tab 140 includes a first end 142 secured to body120 and an opposing second end 144 through which an opening 146 isformed. As shown in FIG. 2, when filter assembly 106 is positionedwithin support housing 108, a hanger 238 can be received within acorresponding opening 146 of each hanging tab 140 to support container112 within support housing 108.

Hanging tabs 140 can be attached to body 120 or integrally formedtherewith. Hanging tabs 140 can be made of the same material as body120, if desired. In embodiments in which body 120 is comprised ofpanels, hanging tabs 140 can be attached to body 120 by being weldedbetween the panels. In other embodiments, hanging tabs 140 can bemounted on the outside of body 120 such as by welding or adhesion.

As shown in FIG. 3, one or more inlet ports can be mounted on top endwall 134 of body 120. In the depicted embodiment, an inlet port 150 isshown. Inlet port 150 comprises a barbed tubular stem 152 having aflange 154 radially encircling and outwardly projecting therefrom. Inletport 150 bounds a fluid passageway 155 that extends therethrough. Duringassembly, a hole is made through top end wall 134 for the port. The stem152 of port 150 is then passed through the hole until flange 154 restsagainst top end wall 134. Conventional welding or other sealingtechniques are then used to seal each flange 154 to top end wall 134.During use, stem 152 can be selectively coupled with a tube or containerfor delivering material into and/or out of compartment 126.

Mounted on bottom end wall 136 of body 120 is an outlet port 156.Similar to inlet port 150, outlet port 156 comprises a barbed tubularstem 158 having a flange 160 radially encircling and outwardlyprojecting therefrom. Outlet port bounds a fluid passageway 162 thatextends therethrough. As with inlet ports 150, during assembly a hole isformed in bottom end wall 136. Outlet port 156 is seated within the holeso that flange 160 rests against bottom end wall 136. Again,conventional welding or other sealing technique is then used to sealflange 160 to bottom end wall 136. During use, stem 158 is selectivelycoupled with an outlet tube for delivering material out of compartment126.

It is appreciated that any number of inlet ports 150 or outlet ports 156can be formed on body 120 and that a variety of different types andsizes of ports can be used depending on the type of material to bedispensed into compartment 126 and how the material is to be dispensedtherefrom. The ports 150 and 156 can also be located at differentlocations on body 120 such as side wall 128.

Filter port 151 also functions as an inlet port. Specifically filterport 151 includes a flange 153 mounted to top end wall 134. A tubularfirst stem 153 upwardly projects from one side of flange 157 and has anannular barb formed on the end thereof. A tubular second stem 172projects from an opposing side of flange 157 so as to extend downwardinto compartment 126. A support flange 180 encircles and radiallyoutwardly projects from the end of second stem 172. Turning to FIG. 4,filter port 151 has an inside surface 176 that bounds a fluid passageway179 extending therethrough, i.e., fluid passageway 179 extends throughfirst stem 153, flange 157, second stem 172 and support flange 180.Filter port 151 can be integrally formed as a single unitary structureor can comprise two or more parts secured together. Support flange 180has a lower face 182 and an opposing upper face 184 that both radiallyextend to an outside face 186. An annular groove 188 can be recessed onoutside face 186 for mounting filter 170 thereto, as discussed below.

Filter 170 comprises a body 190 having an interior surface 192 thatbounds a compartment 193 and an opposing exterior surface 194. A mouth196 is formed on body 190 so as to communicate with compartment 193. Inone embodiment, filter 170 is flexible and can be in the form of aporous bag or sock. Filter 170 is attached to filter port 151 byinserting support flange 180 within mouth 196. A connector 202 such as aclamp, cable tie crimp ring, strap, or the like is then positioned overfilter 170 and tightened so as to secure filter 170 within groove 188.In alternative embodiments, it is appreciated that other conventionalmethods can be used to secure filter 170 to filter port 151. Forexample, filter 170 can be secured to filter port 151 by welding,adhesive or the like. In other embodiments, support flange 180 can beeliminated and filter 170 can be attached directly to second stem 172.In still other embodiments, support flange 180 and second stem 172 canboth be eliminated and filter 170 can be attached to an extended versionof flange 157.

Lower surface 182 of support flange 180 and interior surface 192 offilter 170 together bound an inlet chamber 204 that is fluidly coupledwith fluid passageway 179. As discussed below in greater detail, duringuse a mixture of cultured solution and associated microcarriers can bedelivered to inlet chamber 204 through filter port 151. Filter 170comprises a material that will allow the cultured solution to passtherethrough while preventing the microcarriers from passingtherethrough. As such, the microcarrier are collected within inletchamber 204 of body 190. Filter 170 can be comprised of a porousmaterial, such as a mesh, netting, perforated sheets, lattice type ofmaterial, or any other material that will allow the cultured solution topass therethrough while preventing the associated microcarriers frompassing therethrough. To enable the cells to pass therethrough butprevent the microcarriers from passing therethrough, filter 170 istypically made of a material, having pores in the size of about 15microns to about 100 microns, with about 30 microns to about 100 micronsbeing common. If desired, filter 170 can be expandable and/orresiliently stretchable. Examples of materials that can be used forfilter 170 include polyester (PET), polyamide (PA), polypropylene (PP),and polyetheretherketone (PEEK). Other materials can also be used.

In alternative embodiments, it is appreciated that part or all of filter170 can be rigid or semi-rigid. For example, filter 170 can comprisebody 190 formed from a porous flexible material while a rigid ring ismounted to body 160 and encircles mouth 196. The rigid ring could thenbe used to secure filter 170 to filter port 151 such as by threadedconnection, bayonet connection, snap fit connection, press fitengagement, crimped engagement or the like. In other embodiments, filter170 can be comprised of a rigid material. For example, filter 170 can bemolded from a plastic, metal, or composite material, that has holesformed therethrough through which the cultured fluid can pass but themicrocarriers cannot.

Returning to FIG. 3, as a result of filter 170 being coupled with filterport 151 which is attached to top end wall 134, filter 170 is suspendeddown into compartment 126. When disposed within compartment 126, filter170 essentially divides compartment 126 into two chambers—inlet chamber204 of filter 170, and an outlet chamber 206. Outlet chamber 206 is theportion of compartment 126 external to inlet chamber 204 and fluidpassageway 178. As such, fluid flows from inlet chamber 204 to outletchamber 206 through filter 170.

In one embodiment, filter 170 is sized and positioned so as to besuspended above bottom end wall 136 of container 112 and away fromsidewall 128, as shown in FIG. 3. In some embodiments it can bedesirable to keep filter 170 away from bottom end wall 136 and side wall128 since contacting filter 170 against a structure can cause blockingof that portion of filter 170 which can decrease fluid flow throughfilter 170. In some embodiments, filter 170 remains above bottom endwall 136 during use so as to not contact bottom end wall 136. In otherembodiments, filter 170 may contact bottom end wall 136 and/or side wall128 such as after a portion of the microcarriers have been collected.

If an expandable material is used for filter 170, the weight of themicrocarriers may cause filter 170 to expand downward and outward asmore microcarriers are received, as discussed below. However, by beingsuspended from top end wall 134, filter 170 can in some embodiments beconfigured to remain above bottom end wall 136 even when expanded, asdiscussed in more detail below.

Support housing 108 can be used to support filter assembly 106 or any ofthe filter assemblies discussed herein. This can be especially helpfulif container 112 is flexible, as support housing 108 can provide rigidsupport for container 112. Returning to FIG. 2, support housing 108generally includes a substantially rigid receptacle 210 seated on adolly 212. As depicted, receptacle 210 is configured to receive andsupport filter assembly 106.

Turning to FIGS. 5 and 6, receptacle 210 comprises a substantiallycylindrical side wall 214 that extends from an upper end 216 to anopposing lower end 218. As depicted in FIG. 6, receptacle 210 includes afloor 220 formed inside of receptacle 210 at a position between upperend 216 and lower end 218. Floor 220 has a substantially frustoconicalconfiguration. More specifically, floor 220 has a frustoconical portion221 with a top surface 222 that extends between an inner edge 224 and anopposing outer edge 226. Floor 220 also includes a flat base portion 223inwardly extending from frustoconical portion 221. Base portion 223bounds a central opening 228 extending through floor 220. Outer edge 226is integrally formed with or is otherwise connected to side wall 214.The slope of floor 220 functions in part as a funnel to direct allmaterial toward central opening 228. In alternative embodiments, floor220 can be flat, cupped, irregular, or other desired configurations.

Side wall 214 of receptacle 210 has an interior surface 230 disposedabove floor 220. Interior surface 230 and floor 220 bound first chamber232 formed in upper end 216 of receptacle 210. First chamber 232 issized to receive container 112 and can thus have a corresponding size.Depicted in FIG. 5, upper end 216 of receptacle 210 terminates at anupper edge 234 that bounds an opening 236 to first chamber 232.

As shown in FIG. 5, an optional annular lid 250 can be removablydisposed over upper edge 234 so as to selectively close opening 236.Clamps 252 can be used to selectively secure lid 250 to receptacle 210.Lid 250 can include one or more holes 253 extending therethrough. Holes253 can be configured to align with ports 150 and 151 of container 112so that inlet tubes can extend therethrough to attach to ports 150 and151 and pass fluid into filter assembly 106.

As previously mentioned, one or more hangers 238 can be secured to lid250 or sidewall 214 of receptacle 210 at or near upper edge 234 toreceive the corresponding hanging tabs 140 of filter assembly 106. Forexample, as shown in FIG. 6, hangers 238 can be in the form of hookspositioned on interior surface 230 to receive hanging tabs 140positioned on container 112, as shown in FIG. 2. As shown in FIG. 2,each hanger 238 is positioned on interior surface 230 so as tocorrespond to the position of one of the hanging tabs 140 when filterassembly 106 is positioned within first chamber 232. Hangers 238 can beattached to receptacle 210 by using screws, adhesive, welding or otherknown attachment methods.

When it is desired to remove filter assembly 106 from support housing108, hanging tabs 140 can simply be disconnected from hangers 238 toallow filter assembly 106 to be removed. It is appreciated that hangers238 can come in a variety of different forms. For example, hangers 238can comprise hook that connect to hanging tabs 140 and then catchesdirectly onto edge 234 of receptacle 210 for supporting filter assembly106. In this embodiment, hangers are not fixed to receptacle 210. Instill other embodiments, hangers 238 can comprise hooks or other typesof projections or fasteners that are mounted on the exterior surface ofsidewall 214. In this embodiment, hanging tabs 240 can pass over edge234 and then connect to hangers 238.

Depicted in FIG. 18 is another alternative embodiment for the hangers.Specifically, a retention ring 540 is used for supporting container 112within first chamber 232 of receptacle 210. Retention ring 540 comprisesa substantially C-shaped ring body 542 that terminates at opposing endshaving flanges 544A and 544B formed thereat. A fastener 546 extendsthrough flanges 544A and B and can be used for selectively drawing andsecuring flanges 544A and B together. In one embodiment, fastener 546can comprise a bolt and nut assembly. In alternative embodiments,fastener 546 can comprise a clamp, latch, or any other conventionalfastener that achieves the desired objective.

Ring body 542 is typically in the form of a narrow band having an insideface 548 and an opposing outside face 550. A plurality of spaced aparthangers 552 are mounted on inside face 548 of ring body 542. In oneembodiment, each hanger 552 comprises a elongated pin having a first end554 that is secured, such as by welding, at a central location on insideface 548. Each pin also comprises an opposing second end 556 thatprojects up above ring body 540. If desired, second end 556 of each pincan be rounded. Although not required, in one embodiment a plurality ofspaced apart notches 558 are recessed on the bottom edge of ring body542 such that the top of each notch 558 is disposed adjacent to firstend 554 of a corresponding hanger 552.

During use, fastener 546 is loosened so as to expand the size of ringbody 542. Ring body 542 is then positioned on upper end 476 ofreceptacle 210 so that ring body 542 encircles the exterior surface ofside wall 214 at upper end 216. In this configuration, first end 554 ofeach hanger 552 rests on top of upper edge 234 of side wall 214 so thatretention ring 540 is properly positioned. If desired, a flange can beformed at first end 554 of each hanger 552 for receiving upper edge 234.Notches 558 permit a visual inspection to ensure that ring body 542 isproperly seated. Fastener 546 is then used to clamp retention ring 540on side wall 214. As container 112 (FIG. 3) is inserted within firstchamber 232, second end 556 of each hanger 552 is passed through opening146 of a corresponding hanging tab 140 (FIG. 3) so that container 112 issupported within first chamber 232.

In still other embodiments hangers 238 can be in the form of microhookand loop systems (commonly known as VELCRO), threaded connections,clamps, or the like that connect hanging tabs 140 to receptacle 210.

As shown in FIG. 6, side wall 214 also has an interior surface 254formed below floor 220. Interior surface 254 and floor 220 bound asecond chamber 256 disposed at lower end 218 of receptacle 210. Anaccess port 260 extends through side wall 214 at lower end 218 ofreceptacle 210 so as to provide side access to second chamber 256. Inalternative embodiments, the portion of side wall 214 extending belowfloor 220 can be replaced with one or more spaced-apart legs or othersupports that elevate floor 220 off of the ground, dolly 212, or othersurface on which receptacle 210 rests.

In the embodiment depicted, receptacle 210 comprises a barrel moldedfrom a polymeric material. In alternative embodiments, receptacle 210can be comprised of metal, fiberglass, composites, or any other desiredmaterial. Furthermore, although receptacle 210 is shown as having asubstantially cylindrical configuration, receptacle 210 can besubstantially boxed shaped or have a transverse configuration that ispolygonal, elliptical, irregular, or any other desired configuration.

As depicted in FIG. 5, dolly 212 comprises a frame 262 having aplurality of wheels 264 mounted thereon. Dolly 212 enables easy movementof receptacle 210. In alternative embodiments where it is not necessaryor desired to move receptacle 210, wheels 264 and/or frame 262 can beeliminated. In this regard, receptacle 210 can sit on a ground surfaceor any other desired structure. As shown in FIG. 6, lower end 218 ofreceptacle 210 is received on dolly 212 so as to be stably supportedthereby.

Before use, filter assembly 106 can be positioned within first chamber232 of receptacle 210 so that outlet port 156 can be received withincentral opening 228 extending through floor 220 of receptacle 210, asdepicted in FIG. 7.

It is typically desirable that when filter assembly 106 is receivedwithin first chamber 232, container 112 is at least generally uniformlysupported by floor 220 and side wall 214 of receptacle 210 whencontainer 112 is at least partially filled with a fluid. Having at leastgeneral uniform support of container 112 by receptacle 210 helps topreclude failure of container 112 by hydraulic forces applied tocontainer 112 when filled with a solution.

Hanging tabs 140 disposed on top end wall 134 are looped over hangers238 disposed on interior surface 230 of receptacle 210 to suspendcontainer 112 within first chamber 232. As such, container 112 may notextend all the way down to floor 220 until fluid is introduced intocontainer 112. Before container 112 is disposed within first chamber232, an outlet tube 270 can be connected to outlet port 156. Outlet tube270 extends through central opening 228 and can extend out from supporthousing 108 through access port 260.

As noted above, filter 170 is suspended from top end wall 134 ofcontainer 112 by virtue of its coupling with filter port 151. Becausefilter 170 is indirectly attached to top end wall 134, filter 170 isgenerally suspended above bottom end wall 136 of container, as shown inFIG. 7.

An inlet tube 272 is coupled with first stem 153 of filter port 151.Either before or after filter assembly 106 has been positioned withinfirst chamber 232, inlet tube 272 can be coupled in a sterile fashionwith bioreactor 102 (FIG. 1). During use, a mixture of the culturedsolution and the associated microcarriers from bioreactor 102 isintroduced into inlet chamber 204 of filter assembly 106 through inlettube 272. The cultured solution of the mixture, including the detachedcells, passes through filter 170 and into outlet chamber 206.

More specifically, the mixture passes through fluid passageway 179 infilter port 151 and is received by inlet chamber 204 of filter 170, asdepicted in FIGS. 8A-8C. As shown in FIG. 8A, as the mixture is firstreceived within inlet chamber 204, as denoted by arrow 280, inletchamber 204 is completely or mostly devoid of microcarriers and thecultured solution can freely pass through filter 170 through the sidesand bottom thereof, as indicated by arrows 282. As shown in FIGS. 8B and8C, as more mixture flows into inlet chamber 204, the microcarriers(shown as a group of beads 284) within the mixture are retained andbegin to accumulate at the bottom of inlet chamber 204. The culturedsolution continues to pass through filter 170. However, the majority ofthe fluid passes out through the side portion of filter 170 that isabove the accumulated microcarriers, as shown by arrows 286 and 288 inFIGS. 8B and 8C. This is because the accumulated microcarriers at leastpartially block the flow of fluid through the portion of filter 170 thatthey rest against. Thus, the configuration of filter 170 permits anefficient collection of microcarriers while still permitting a free flowof cultured solution through filter 170.

Filter 170 is typically sized so that all of the microcarriers frombioreactor 102 can be collected within inlet chamber 204 while stillallowing a portion of filter 170 to be unobstructed by microcarriers sothat the cultured solution can freely pass therethrough. Alternatively,a filter assembly 106 can be used until inlet chamber 204 issufficiently filled with microcarriers that the cultured fluid can nolonger pass through filter 170 as a desired processing rate. Filterassembly 106 can then be replaced with a new filter assembly 106 and theprocess continued.

If an expandable material is used for filter 170, the weight of themicrocarriers can cause filter 170 to expand downward and outward, asdepicted in FIGS. 8B and 8C. This expansion can cause filter 170 tobecome more elongate, thereby increasing the surface area of filter 170and allowing more cultured solution to flow through the sides of filter170 as to enable more microcarriers to be retained within inlet chamber204.

After the cultured solution passes through filter 170, the culturedsolution can either be retained within outlet chamber 206 or can passdirectly out of container 112 through outlet port 156 and outlet tube270. Once all of the cultured solution has been processed through filterassembly 106, filter assembly 106 can be removed from support housing108 and discarded with the microcarriers contained therein.Alternatively, filter assembly 106 can be cut open and the microcarriersremoved and recycled for further use. By forming filter assembly 106from a disposable container and filter, the inventive system eliminatesthe need for cleaning or sterilizing the filtering system betweendifferent batches of culturing solution.

In some systems, the weight of the microcarriers combined with the forcecaused by the downward motion of the incoming mixture can cause a strainon container 112 where filter port 151 attaches to top end wall 134. Toalleviate this strain between filter port 151 and top end wall 134,filter port 151 can also be directly attached to receptacle 210 insteadof or in conjunction with the hanging tabs and hangers, discussed above.For example, in the embodiment shown in FIG. 9, a hanging flange 292 isattached to or is integrally formed with stem 153 of filter port 151.Hanging flange 292 outwardly projects from stem 153 above flange 157 sothat hanging flange 292 will be positioned outside of compartment 126when filter port 151 has been attached to top end wall 134. Hangingflange 292 has a top surface 294 and an opposing bottom surface 296 andbounds an opening 298 extending therethrough. Similar to hanging tabs140, discussed previously, opening 298 of hanging flange 292 can belooped over one of hangers 238 disposed on receptacle 210 to suspendfilter port 151 and filter 170 from the top end of receptacle 210. Toposition opening 298 of hanging flange 292 adjacent to a hanger 238,filter port 151 can be positioned adjacent to the perimeter edge of topend wall 134, as shown in the depicted embodiment.

All or portions of hanging flange 292 can be flexible or substantiallyrigid. If hanging flange 292 is substantially rigid, the portion ofhanging flange 292 that includes opening 298 can be shaped to form anangle with respect to the rest of second flange 292, as shown in thedepicted embodiment, to more easily facilitate the attachment of hangingflange 292 to hanger 238 and to help keep filter 170 vertical. It isappreciated that all of the other methods as discussed above forsecuring hanging tabs 140 to receptacle 210 can also be used to securehanging flange 292 to receptacle 210.

In one embodiment, the hanging flange 292 is replaced by an attachmentdevice that is removable and reusable. For example, as shown in FIGS.10A and 10B, the hanging flange 292 can be replaced by a clamp assembly300 that removably attaches to stem 153. Clamp assembly 300 includes apair of mating arms 302 and 304 that rotate about a hinge 306 positionedat one end 308 of the pair of arms. Hinge 306 includes a tubular hingepin 307 that bounds an opening 314. At the other end 310 of arms 302/304is a securing mechanism, such as a screw assembly 312, to tighten arms302 and 304 together around stem 153. During use, opening 314 isadvanced over hanger 316 so that hanger 316 supports filter port 151 andattached container 112. If desired, hanger 316 can have substantiallyhard (i.e., about 90 degree) angles to facilitate keeping inlet port 151and filter 170 in a generally vertical orientation. It is appreciatedthat opening 314 need not be located within hinge pin 307 but andotherwise be formed on clamp assembly 300.

In another embodiment, a removable attachment device can be used with amodified hanging flange and hanger. For example, as shown in FIG. 17A,hanger 316 can be replaced by a hanger 500 that is also secured tointerior surface 230 of sidewall 214 at upper end 216 of receptacle 210.Hanger 500 includes a flange 502 attached to and projecting fromsidewall 214 and a substantially C-shaped retainer 504 disposed at theend thereof. Retainer 504 includes a stem 506 and a flange 508 radiallyoutwardly projecting therefrom. Both stem 506 and flange 508 have asubstantially C-shaped configuration.

Turning to FIG. 17B, a hanging flange 510 is integrally formed with stem153 of inlet port 151. Hanging flange 510 is similar to hanging flange292, discussed above, except that hanging flange 510 may omit openingsextending therethrough, if desired, and is typically flat. Hangingflange 510 radially encircles and outwardly projects from stem 153 aboveflange 157. Hanging flange 510 has a top surface 512 and an opposingbottom surface 514. For receptacle 210 to support filter port 151,filter port 151 can be positioned so that stem 153 extends through stem506 of support hanger 500 and the bottom surface 514 of hanging flange510 rests upon flange 508 of hanger 500. In this position, hanger 500can provide the desired support for container 112.

To secure filter port 151 to hanger 500, a clamp assembly 516 can beused. Clamp assembly 516 can be similar to clamp assembly 300, discussedabove, with a few differences. As shown in FIG. 17C, clamp assembly 516includes a pair of mating arms 518 and 520 that rotate about a hinge 522positioned at one end 524 of the pair of arms. At the other end 526 ofthe arms is a securing mechanism, such as a screw assembly 528, totighten arms 518 and 520 together. An annular channel 530 is formed onthe inside surface of arms 518 and 520.

Returning to FIG. 17B, to secure filter port 151 to support 500, arms518 and 520 (collectively denoted as 519) are positioned around flange508 and hanging flange 510 so that when clamp assembly 516 is closed andtightened, these structures are received within annular channel 530 andsecurely held together. A gasket or the like can also be positionedwithin annular channel 530, if desired, to form a more secure connectionbetween clamp assembly 516 and flange 508 and hanging flange 510. Othertypes of securing methods and devices can alternatively be used tosecure filter to receptacle 210.

FIG. 19 depicts another embodiment of a filter assembly 600. Likeelements between filter assembly 600 and filter assembly 106 areidentified by like reference characters. Similar to filter assembly 106,filter assembly 600 comprises a filter 602 disposed within container 112and attached thereto using a filter port 604. However, instead of beingdirectly attached to filter port 604, filter 602 includes an inlet port606 that is attached to filter port 604 using a dip tube line 608.

Similar to filter port 151, filter port 604 includes barbed first stem153 upwardly projecting from a top side of flange 157. A barbed secondstem 610 projects from the bottom side of flange 157 so as to extenddownward into compartment 126. Second stem 610 is generally similar tofirst stem 153 except that second stem 610 extends in the oppositedirection from flange 157. Filter port 604 has an inside surface 612that bounds a fluid passageway 614 extending therethrough, i.e., fluidpassageway 614 extends through first stem 153, flange 157, and secondstem 610. Filter port 604 can be integrally formed as a single unitarystructure or can comprise two or more parts secured together.

Turning to FIG. 20, filter 602 comprises a two-dimensional pillow stylebag 616 wherein two sheets 618 and 620 of material are placed inoverlapping relation and the two sheets are bounded together at theirperipheries to form an internal chamber 622.

Turning to FIG. 21 in conjunction with FIG. 20, sheet 618 has aninterior surface 624 and an opposing exterior surface 626 extending to aperimeter edge 628. Sheet 618 is comprised of a flexible material suchas polyethylene or other polymeric sheets, similar to body 120 ofcontainer 112. The material can be comprised of a single ply material orcan comprise two or more layers which are either sealed together orseparated to form a double wall container. Where the layers are sealedtogether, the material can comprise a laminated or extruded material.The laminated material comprises two or more separately formed layersthat are subsequently secured together by an adhesive. Sheet 618 can becomprised of the same type of materials as discussed above with regardto body 120 of container 112. In one embodiment, sheet 618 is comprisedof the same material as body 120. Although shown in the depictedembodiment as being substantially circular, it is appreciated that sheet618 can have virtually any desired shape. Similarly, it is appreciatedthat sheet 618 can have virtually any desired size.

A hole 630 is formed in sheet 618 so as to extend therethrough betweeninterior and exterior surfaces 624 and 626. Hole 630 is sized so as tobe able to receive inlet port 606. Although hole 630 is shown in thedepicted embodiment as being substantially centered on sheet 618, thisis not required. Hole 630 can be positioned anywhere on sheet 618 andcan be any size that will accommodate inlet port 606.

Sheet 620 has an interior surface 632 and an opposing exterior surface634 extending to a perimeter edge 636. Sheet 620 is comprised of aflexible porous material that allows the cultured solution to passthrough, yet prevents microcarriers from passing through. For example,sheet 620 can be comprised of a mesh material made of a polymericmaterial, such as those materials discussed above with respect to filter170. Other polymeric and non-polymeric materials can also be used.Furthermore, pore size ranges of the mesh can be similar to thosediscussed above with respect to filter 170. Sheet 620 can be expandableand/or resiliently stretchable, if desired. Sheet 620 is generally sizedand shaped to match the size and shape of sheet 618, although this isnot required.

Inlet port 606 is similar to inlet ports 150 positioned on body 120 (seeFIG. 19). As such, as shown in FIG. 20, inlet port 606 comprises abarbed tubular stem 152 having a flange 154 radially encircling andoutwardly projecting therefrom. Inlet port 606 bounds a fluid passageway155 that extends therethrough. During assembly, hole 630 is made throughsheet 618 for the port. Stem 152 of inlet port 606 is then passed upthrough hole 630 until flange 154 rests against interior surface 624 ofsheet 618. Conventional welding or other sealing techniques are thenused to seal flange 154 to sheet 618.

After inlet port 606 has been secured to sheet 618, interior surfaces624 and 632 of sheets 618 and 620 are positioned against each other, asshown in FIG. 20, and corresponding perimeter edges 628 and 636 areattached or secured together using heat energies, RF energies, sonics,or other sealing energies. Adhesives or other types of securing orattaching devices or methods can also be used. Dashed lines 638 of FIG.21 depicts the perimeter portions of sheets 618 and 620 that are securedtogether during assembly. When secured, inside surfaces 624 and 632together bound compartment 622, with material being deliverablethereinto via inlet port 606.

Returning to FIG. 19, once filter 602 has been assembled, filter 602 canbe positioned within container 112. That is, during assembly of filterassembly 600, stem 152 of filter 602 can be fluidly coupled with secondstem 610 of filter port 604 using dip tube line 608. Container 112 canthen be sealed closed.

Similar to filter assembly 106, filter assembly 600 can be positionedbefore use within first chamber 232 of receptacle 210, and the top ofcontainer 112 can be attached to receptacle 210 using hanging tabs orother hanging elements. Also similar to filter assembly 106, outlet tube270 can be connected to outlet port 156 and extended through centralopening 228 and out from support housing 108 through access port 260.

During use, inlet tube 272 is coupled with bioreactor 102 (FIG. 1) sothat a mixture of cultured solution and associated microcarriers can beintroduced into inlet chamber 622. The cultured solution portion of themixture passes through filter 602 and into outlet chamber 206, where thefluid can collect or exit container 112 through outlet port 156 andoutlet tube 270. Filter 602 causes the microcarriers to be retainedwithin inlet chamber 622 to be discarded or recycled for further use.

More specifically, the mixture passes through filter port 604 and diptube line 608 to arrive at filter 602. The mixture passes through inletport 606 and is received by inlet chamber 622 through fluid passageway155, as depicted in FIGS. 22A-22C. As shown in FIG. 22A, as the mixtureis first received within inlet chamber 622 as denoted by arrow 640,inlet chamber 622 is completely or mostly devoid of microcarriers andthe cultured fluid can pass through porous sheet 620 through the bottomthereof, as indicated by arrows 642. Filter bag 602 can be substantiallyflat, as there is no weight to push it downward.

As shown in FIG. 22B, as more mixture flows into inlet chamber 622, themicrocarriers 284 within the mixture are retained and begin toaccumulate at the bottom of inlet chamber 622. The weight of themicrocarriers 284 can cause filter 602 to elongate and extend furtherdownward. The cultured solution continues to pass through porous sheet620. However, the majority of the fluid passes out through the sideportions of porous sheet 620 that is above the accumulatedmicrocarriers, as shown by arrows 644.

As shown in FIG. 22C, as more microcarriers 284 continue to accumulateat the bottom portion of filter 602, the weight of the microcarriers maycause filter 602 to further elongate and fluid can continue to flowthrough the upper portion of sheet 620 not covered by microcarriers, asdenoted by arrows 646. If an expandable material is used for poroussheet 620, the weight of the microcarriers can cause porous sheet 620 toexpand further downward. This expansion can increase the surface area ofporous sheet 620 which can allow for more cultured solution to flowthrough the sides of porous sheet 620 and more microcarriers can beretained.

FIGS. 23A and 23B depict another embodiment of a filter 650 based onfilter 602 but using an alternative filter sheet configuration. Thesheets of filter 650 are depicted as being rectangular. However, asdiscussed above, this is exemplary only and the sheets can be of anysize and shape. Similar to filter 602, filter 650 also includes flexiblesheet 618 and porous sheet 620. However, filter 650 also includes apicture-frame sheet 652 positioned against exterior surface 634 ofporous sheet 620 so as to sandwich the edges of porous sheet 620 betweensheets 618 and 652, as particularly shown in FIG. 23B. Sheet 652 has aninterior surface 656 and an opposing exterior surface 658. Sheet 652bounds an opening 660 extending through sheet 652 between interior andexterior surfaces 656 and 658. Sheet 652 can be comprised of similarmaterials as sheet 618 and can be used to aid in securing porous sheet620 to sheet 618. That is, sheet 652 may be useful if the porousmaterial does not form a secure attachment to sheet 618. Sheet 652 canprovide a better attachment to sheet 618 and the edges of sheet 620 canbe better attached due to its being sandwiched between sheets 618 and652.

In an alternative embodiment, shown in FIG. 23C, sheet 652 can beomitted and sheet 618 can be sized to be larger than sheet 620. Theportion of perimeter edge 628 of sheet 618 that extends beyond perimeteredge 636 of sheet 620 can be folded over perimeter edge 636 so as torest against exterior surface 634 of porous sheet 620 and form thepicture-frame.

FIGS. 24A and 24B depict another embodiment of a filter 670 based onfilter 602 but using another alternative filter sheet configuration.Filter 670 is similar to filter 650, except that sheet 618 is replacedwith a sheet 672 that bounds an opening 674 extending therethrough. Toprevent microcarriers from passing through opening 674, another poroussheet 676 is also included to go along with porous sheet 620. Sheet 676is sized similar to opening 674 and is secured to the interior surfaceof sheet 672. Porous sheet 676 does not cover hole 630 so that thecultured solution can pass through hole 630 and into internal chamber622, which is now bounded by porous sheet 676 as well as sheets 672 and620, as particularly shown in FIG. 24B. This embodiment provides moresurface area for the solution to pass through than filters 602 or 650,as solution can also pass through porous sheet 676 covering opening 674on top sheet 672. As shown in the depicted embodiment, hole 630 can bepositioned near the perimeter edge of sheet 672 to allow opening 674 tohave a larger surface area, if desired.

As with filter 650, picture frame sheet 652 can alternatively be omittedand sheet 672 can be sized to be larger than sheets 620 and 676. Theportion of the perimeter edge of sheet 672 that extends beyond perimeteredge 636 of sheet 620 can be folded over perimeter edge 636 so as torest against exterior surface 634 of porous sheet 620 and form thepicture-frame in a manner similar to that discussed above with regard tofilter 650.

As with filter port 151, filter port 604 can also be directly attachedto receptacle 210 instead of or in conjunction with the hanging tabs andhangers, as discussed above with reference to FIGS. 9-10B and 17A-17C.It is appreciated that the filter embodiments shown in FIGS. 20-24B areexemplary only and that other two-dimensional pillow style bags can alsobe used. It is also appreciated that instead of using a dip tube line608 to attach filter port 604 to inlet port 606, a single port can beused to directly attach top sheet 618 or 672 to body 120 of container112.

FIG. 11 depicts another embodiment of a filter assembly 320. Likeelements between filter assembly 320 and filter assembly 106 areidentified by like reference characters. Filter assembly 320 includes afilter 322 that attaches directly or indirectly to the body 120 ofcontainer 112 to divide compartment 126 into an inlet chamber 324 and anoutlet chamber 326. Filter 322 comprises a sheet of a porous materialthat will allow the cultured solution to pass therethrough but willprevent the microcarriers from passing therethrough. Filter 320 can becomprised of a sheet of the same materials as discussed above withregard to filter 170. Furthermore, filter 322 can be expandable and/orresilient, if desired. Filter 322 can be attached to or integrallyformed with container 112.

In embodiments in which body 120 is comprised of two or more panels,filter 322 can be attached to body 120 by placing filter 322 between thepanels so that as the panels are welded together, filter 322 isconcurrently welded therebetween. For example, if container 122 is apillow style bag which is comprised of two overlying panels, filter 322can be placed between the overlying panels. As the perimeter edges ofthe panels are welded together to form the bag, filter 322 isconcurrently secured to or welded into the weld matrix so that filter322 bisects the compartment of the pillow bag. This method isparticularly useful where filter 322 is comprised of a perforated sheetof a polymeric material but can also be used with netting and othermaterials. In an alternative method, a perimeter edge of filter 322 canbe secured on a face of a first panel by welding, adhesive, or the like.A second panel can then overlay the first panel and the second panelwelded to the first panel either over top of or adjacent to filter 322.In embodiments where container 122 is comprised of three or more panels,portions of filter 322 can be welded between different panels. Likewise,where container 122 comprises an extruded tube and opposing end panels,filter 322 can be welded or otherwise secured between the tube and oneof the end panels or can be secured to one of the tube or the end panelsand then the tube and end panel secured together.

Continuing with FIG. 11, filter 322 has an inlet surface 328 and anopposing outlet surface 330 that extend from a first end 332 at top endwall 134 of container 112 to a second end 334 at bottom end wall 136 orside wall 128 of container 112. Inlet chamber 324 is bounded by theinterior surface 122 of a portion of container 112 and inlet surface 328of filter 322, and outlet chamber 326 is bounded by the interior surface122 of the remaining portion of container 112 and outlet surface 330 offilter 322. Inlet port 150 is positioned on top end wall 134 so as tofluidly communicate with inlet chamber 324 and outlet port 156 ispositioned on bottom end wall 136 so as to fluidly communicate withoutlet chamber 326. As such, fluid passes through filter 322 as it movesbetween inlet and outlet ports 150 and 156.

Similar to filter assembly 106, filter assembly 320 also incorporatesreceptacle 210 into which container 112 is received. As such, similar tofilter assembly 106, filter assembly 320 can also be configured indifferent shapes, as discussed above and can include hanging tabs andhangers, as discussed above with respect to filter assembly 106. In thisembodiment, however, inlet port 150 would function as filter port 151with regard to being modified or otherwise connected to receptacle 210as discussed above with respect to filter port 151.

Filter 322 is typically comprised of a sheet of flexible material butcould be comprised of a sheet of rigid or semi-rigid material. As such,filter 322 can be substantially planar or have one or more curvesbetween first and second ends 332 and 334. Furthermore, filter 322 canbe substantially taut or substantially loose. In the depictedembodiment, first end 332 of filter 322 is positioned at about themiddle of top end wall 134 and second end 334 is positioned at bottomend wall 136 adjacent side wall 128. Other configurations are alsopossible. For example, first end 332 of filter 322 can be positioned ontop end wall 134 nearer side wall 128, if desired. Also, first end 332or second end 334 or both can be positioned on side wall 128 instead oftop and bottom end walls 134 and 136. Regardless of the positioning offirst and second ends 332 and 334 of filter 322, however, filter 322 ispositioned such that inlet port 150 directly fluidly communicates withinlet chamber 324 and outlet port 156 directly fluidly communicates withoutlet chamber 326.

Similar to filter assembly 106, filter assembly 320 can be positionedbefore use within first chamber 232 of receptacle 210, and the top ofcontainer 112 can be attached to receptacle 210 using hanging tabs orother hanging elements. Also similar to filter assembly 106, outlet tube270 can be connected to outlet port 156 and extended through centralopening 228 and out from support housing 108 through access port 260, asshown in FIG. 11.

During use, inlet tube 272 is coupled with bioreactor 102 (FIG. 1) sothat a mixture of cultured solution and associated microcarriers can beintroduced into inlet chamber 324 therethrough. The cultured solutionportion of the mixture passes through filter 322 and into outlet chamber326, where the fluid can collect or exit container 112 through outletport 156 and outlet tube 270. Filter 322 causes the microcarriers to beretained within inlet chamber 324 to be discarded or recycled forfurther used.

More specifically, the mixture passes through inlet port 150 and isreceived by inlet chamber 324 through fluid passageway 155, as depictedin FIGS. 12A-12C. As shown in FIG. 12A, as the mixture is first receivedwithin inlet chamber 324, as denoted by arrow 340, inlet chamber 324 iscompletely or mostly devoid of microcarriers and the cultured fluid canpass through filter 322 along its entire length into outlet chamber 326,as indicated by arrows 342. The cultured fluid can then pass out ofoutlet chamber 326 through outlet port 156, as denoted by arrow 344.

As more mixture flows into inlet chamber 324, the microcarriers 284begin to accumulate at the bottom of inlet chamber 324 as the culturedfluid continues to pass through filter 322, as shown by arrows 346 and348 in FIGS. 12B and 12C. As can be seen, because second end 334 offilter 322 extends to and is supported by top end wall 134 of container112, fluid can continue to flow through the upper portion of filter 322not covered by microcarriers, as denoted by arrows 348, even as moremicrocarriers may accumulate at the bottom portion of filter 322. If anexpandable material is used for filter 322, the weight of themicrocarriers can cause filter 322 to expand downward and outward, asdepicted in FIGS. 12B and 12C. This expansion increases the surface areaof side surfaces 328 and 330 (FIG. 11) of filter 322 which allows formore cultured solution to flow through the sides of filter 322 and moremicrocarriers to be retained.

FIG. 13 depicts another embodiment of a filter assembly 350incorporating features of the present invention. Again, like elementsbetween different embodiments are identified by like referencecharacters. Filter assembly 350 includes container 112 and a filter 352coupled with an outlet port 388 so as to extend upward into compartment126. Turning to FIG. 14, outlet port 388 is similar to outlet port 156but has an additional stem 390 extending upward from flange 160 (i.e.,in the opposite direction from flange 160 as stem 158). Stem 390 isgenerally collinear with stem 158, although this is not required.

Filter 352 includes a sidewall 356 having an inside surface 358 and anopposing outside surface 360 extending from an open first end 392 to aspaced apart closed second end 394. Inside surface 358 of sidewall 356bounds a fluid passageway 362 extending therethrough. The open first end392 of filter 352 couples with stem 390 so that fluid passageways 162and 362 fluidly couple with each other and combine to form fluidpassageway 364. Stem 158, 390, and filter 352 can be substantiallycollinear, although that is not required. Filter 352 can attach to stem390 by adhesive, welding, threaded connection, press fit, crimping orother known connecting method. In addition, if desired, a channel 396can be formed on the inside surface 358 at first end 392 of filter 352to aid in attaching to stem 390, as in the depicted embodiment.

A plurality of openings 366 extend through sidewall 356 of filter 352that are large enough to allow the cultured solution to flow through,but small enough to prevent the microcarriers from flowing through. Theopenings 366 can encircle and extend all along filter 352 or any portionthereof. In one embodiment, filter 352 comprises a stem that issubstantially rigid so as to prevent filter 352 from collapsing asmicrocarriers build up around it. For example, filter 352 can becomprised of plastic, metal, composite, glass or the like. Openings 366can be formed as part of a molding process or can subsequently bedrilled or otherwise formed. Other methods for forming openings 366 canalso be used.

As shown in FIG. 13, during assembly, a hole is formed in bottom endwall 136. Outlet port 156 is seated within the hole so that filter 352extends upward into compartment 126 and flange 160 rests against bottomend wall 136. Similar to other outlet ports discussed herein,conventional welding or other sealing technique can then be used to sealflange 160 to bottom end wall 136.

Similar to other embodiments discussed herein, filter 352 dividescompartment 126 into two separate chambers—an inlet chamber 368 and anoutlet chamber 370. Fluid passageway 362 corresponds to outlet chamber370. Thus, outlet chamber 370 is fluidly coupled with fluid passageway162 of outlet port 156. Inlet chamber 368 is the portion of compartment126 external to outlet chamber 370. Fluid flows from inlet chamber 368to outlet chamber 370 through filter 352, as discussed below.

As noted above, when outlet port 156 is attached to container 112,filter 352 extends upward into compartment 126. Filter 352 can extend asfar upward into compartment 126 as desired. In some embodiments, filter352 has a length that allows it to contact and, if desired, attach totop end wall 134 of container 112. Other lengths are also possible.Filter 352 can be attached to outlet port 156 by adhesive, threadedconnection or other attachment method. Alternatively, filter 352 can beintegrally formed with outlet port 156.

Similar to the filter assemblies discussed above, filter assembly 350can be positioned before use within first chamber 232 of receptacle 210,and the top of container 112 can be attached to receptacle 210 usinghanging tabs or other hanging elements. Also similar to the filterassemblies discussed above, outlet tube 270 can be connected to outletport 156 and extended through central opening 228 and out from supporthousing 108 through access port 260, as shown in FIG. 13.

Inlet tube 272 is also attached to inlet port 150 and extends tobioreactor 102 (FIG. 2). During use a mixture of cultured solution andassociated microcarriers are introduced into inlet chamber 368 throughinlet port 150. The cultured solution passes through the openings 366(FIG. 14) in the sidewall 356 of filter 352 and into outlet chamber 370.The fluid flows down through fluid passageway 162 of outlet port 156where the fluid can exit container 112 through outlet tube 270. Themicrocarriers, which cannot pass through filter 352, collect at thebottom of container 112.

More specifically, the mixture passes through inlet port 150 and isreceived by inlet chamber 368 through fluid passageway 155, as depictedin FIGS. 15A-15C. As shown in FIG. 15A, as the mixture is first receivedwithin inlet chamber 368, as denoted by arrow 376, inlet chamber 368 iscompletely or mostly devoid of microcarriers and the cultured fluid canpass through filter 352 along its entire length into outlet chamber 370,as indicated by arrows 378. The cultured fluid can then pass out ofoutlet chamber 370 through outlet port 156, as denoted by arrow 380. Asmore mixture flows into inlet chamber 368, the microcarriers 284 beginto accumulate at the bottom of inlet chamber 368 as the cultured fluidcontinues to pass through the filter 352, as shown by arrows 382 and 384in FIGS. 15B and 15C. As can be seen, however, as long as filter 352extends upward beyond the retained microcarriers 284, fluid can continueto flow through the upper portion of filter 352, as denoted by arrows384 even as more microcarriers may accumulate at the bottom portion offilter 352. That is, because filter 352 extends vertically withincontainer 112, at least a portion of filter 352 remains openly exposedto receive the cultured solution even when a lower portion of filter 352may be covered by microcarriers.

After use, filter assembly 350 can be discarded with the microcarriers.Alternatively, container 112 can be opened and the microcarriersrecycled.

FIG. 16 depicts another embodiment of a filter 400 that can be used inplace of filter 352 in filter assembly 350. Similar to filter 352,filter 400 also attaches to outlet port 156. However, instead of beingsubstantially vertical, filter 400 is substantially horizontal. Toaccommodate filter 400, outlet port 156 includes a stem 402 that extendsfrom a proximal end 403 at flange 160 to a spaced apart distal end 404.The distal end 404 of stem 402 flairs out radially so as to be widerthan at the proximal end 403 and has an opening 405 at distal end 404.

A filtering element 407 is positioned over the opening 405 at the distalend 404 of stem 402. Filtering element 407 has an outer surface 406 andan opposing inner surface 408 and can be made of any of the filteringmaterials discussed above. Thus, filtering element 407 permits culturedsolution which includes the detached cells to pass through filteringelement 407 but prevents microcarriers from passing therethrough. Stem402 has an interior surface 410 that together with the inner surface 408of filtering element 407 bounds a compartment 412 that is directlycoupled with fluid passageway 162 of outlet port 156. To accommodate forthe weight of the microcarriers that may accumulate on the filteringmaterial, a framework 414 can be positioned within compartment 412 tobolster filtering element 407 and prevent filtering element 404 fromcollapsing. Framework 414 can be comprised of intermingled struts andwalls or can be a thick material through which fluid can pass.Regardless of its composition, framework 414 is configured to allow thecultured fluid to flow therethrough to outlet port 156. To aid in theflow of the fluid, interior surface 410 can be angled to guide the fluidto the fluid passageway 162.

The present invention may be embodied in other specific forms withoutdeparting from its spirit or essential characteristics. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive. The scope of the invention is, therefore, indicatedby the appended claims rather than by the foregoing description. Allchanges which come within the meaning and range of equivalency of theclaims are to be embraced within their scope.

What is claimed is:
 1. A filter assembly for separating microcarriersfrom a fluid medium, the filter assembly comprising: a collapsiblecontainer bounding a sterile compartment adapted to hold a fluid; aninlet port through which fluid flows into the compartment; an outletport through which fluid flows out of the compartment; and a filterdisposed within the compartment, the filter dividing the compartmentinto an inlet chamber that is fluidly coupled with the inlet port and anoutlet chamber that is fluidly coupled with the outlet port, the filterallowing a medium to pass therethrough but preventing microcarriersdisposed in the medium from passing therethrough.
 2. The filter assemblyas recited in claim 1, wherein the collapsible container comprises aflexible bag.
 3. The filter system as recited in claim 1, wherein thefilter is coupled with the inlet port by a tube.
 4. The filter assemblyas recited in claim 1, wherein the filter is expandable.
 5. The filterassembly as recited in claim 1, wherein the filter is flexible.
 6. Thefilter assembly as recited in claim 1, wherein the filter is comprisedof a mesh material or a perforated polymeric sheet.
 7. The filterassembly as recited in claim 1, wherein the filter is coupled with theinlet port so that any fluid medium passing through the inlet portpasses through the filter.
 8. The filter assembly as recited in claim 1,wherein the filter comprises a porous bag or sock coupled with the inletport.
 9. The filter assembly as recited in claim 1, wherein the filtercomprises: a plurality of sheets, at least one of the sheets beingcomprised of a porous material, the plurality of sheets being boundedtogether at their peripheries to form the inlet chamber; and a filterinlet port through which fluid flows into the inlet chamber, the filterinlet port extending through at least one of the plurality of sheets,the filter inlet port being fluidly coupled with the inlet port.
 10. Thefilter assembly as recited in claim 1, wherein the collapsible containerhas a floor and the filter is suspended above the floor.
 11. A filtersystem comprising: a substantially rigid support housing having a floorwith a side wall upstanding therefrom, the floor and the side wallbounding a chamber; and a filter assembly as recited in claim 1, thefilter assembly being removably disposable within the chamber of thesupport housing.
 12. The filter system as recited in claim 11, whereinthe container is removably attachable to an upper end of the supporthousing.
 13. The filter system as recited in claim 11, wherein the inletport is removably attachable to the support housing.
 14. The filtersystem as recited in claim 13, wherein the filter is coupled with theinlet port.
 15. A filter assembly for separating microcarriers from amedium in which the microcarriers have been added to aid in cell culturedevelopment, the filter comprising: a collapsible container bounding asterile compartment adapted to hold a fluid; a filter port attached tothe collapsible container, the filter port having a fluid passagewayextending therethrough such that a cultured solution havingmicrocarriers therein can pass therethrough; and a filter disposedwithin the sterile compartment and mounted on the filter port so as tofluidly communicate with the fluid passageway of the filter port, thefilter being comprised of a porous material configured to allow acultured solution that includes cells to pass therethrough whilepreventing microcarriers from passing therethrough.
 16. The filterassembly as recited in claim 15, further comprising an outlet portattached to the collapsible container, the outlet port having a fluidpassageway extending therethrough such that the cultured solution canexit the sterile compartment therethrough.
 17. The filter assembly asrecited in claim 15, wherein the filter comprises: a plurality ofsheets, at least one of the sheets being comprised of a porous material,the plurality of sheets being bounded together at their peripheries toform the inlet chamber; and a filter inlet port through which fluidflows into the inlet chamber, the filter inlet port extending through atleast one of the plurality of sheets, the filter inlet port beingfluidly coupled with the filter port.
 18. The filter assembly as recitedin claim 17, wherein the filter inlet port is fluidly coupled with thefilter port by a tube.
 19. The filter assembly as recited in claim 17,wherein the plurality of sheets comprises a first sheet and a secondsheet bounded together at their peripheries, the second sheet beingcomprised of the porous material, the first and second sheets boundingthe inlet chamber.
 20. The filter assembly as recited in claim 19,wherein the plurality of sheets further comprises a third sheet havingan opening extending therethrough, the third sheet being bounded to thefirst and second sheets at the periphery of the third sheet such thatthe second sheet is sandwiched between the first and third sheets at theperiphery of the second sheet.
 21. The filter assembly as recited inclaim 19, wherein the first sheet has an opening extending therethrough,and the plurality of sheets further comprises a third sheet, the thirdsheet being comprised of the porous material, the third sheet beingbounded to the first sheet to cover the opening therein, the third sheetalso bounding the inlet chamber.
 22. The filter assembly as recited inclaim 19, wherein the perimeter edges of the first sheet are wrappedaround the perimeter edges of the second sheet and bounded thereto. 23.A filter system comprising: a substantially rigid support housing havinga floor with a side wall upstanding therefrom, the floor and side wallbounding a chamber; and the filter assembly as recited in claim 15, thefilter assembly being removably disposed within the chamber.
 24. Afilter assembly for separating microcarriers from a medium in which themicrocarriers have been added to aid in cell culture development, thefilter comprising: a collapsible bag bounding a sterile compartmentadapted to hold a fluid; a filter comprised of a porous sheet offlexible material, the filter being directly coupled with thecollapsible bag so as to divide the compartment into an inlet chamberand an outlet chamber; an inlet port coupled with the collapsible bag soas to communicate with the inlet chamber; and an outlet port coupledwith the collapsible bag so as to communicate with the outlet chamber.